DESCRIPTION(adapted from applicant's abstract): This proposal examines two kinds of working memory-memory for shape and space- at the cellular level using a single unit recording technique in awake behaving rhesus monkeys. Much work suggests that perceptual processing proceeds along two cortical paths in temporal and parietal cortices, often characterized as the 'what' and where pathways, respectively. Both pathways project to regions of prefrontal cortex. Previous work has not been careful in the manipulation of featural and spatial working memory requirements and no study has compared cell response to both kinds of working memory within the same cortical area with identical visual conditions. Using the proposed paradigms, we have just finished recording from posterior parietal and inferior temporal cortices of animals performing these tasks where we found quite different patterns of findings. This study will provide valuable information as to whether working memory of shape and space are physiologically segregated in prefrontal cortex. We will also be able to report exactly how these types of working memory modulate cell response and how this relates to the sensory and motor response of the cell. Further, we will be able to compare the findings directly to data we have obtained from posterior parietal and inferior temporal cortices. Prefrontal cortex has been implicated in a variety of human neurological and mental diseases, including Parkinson's disease. Huntington's chorea, Korsakoff's disease, and schizophrenia. Little work in the neuropsvchology of memory has focused on short-term or working memory. Characterization of mechanisms related to working memory in prefrontal cortex may prove useful for better understanding what role short-term or working memory deficits play in the cognitive and psychiatric abnormalities that are associated with these conditions.